> How much

Some jobs are process oriented in which the value contributed is in volume and efficiency.

>> achieve what I'm supposed to achieve

Other jobs are development oriented in which value contributed in defining the process or the end result of the process.

It seems like the former is more amenable to "regular hours" and the latter to great swings in hours spent in effort directly related to a specific purpose.

Incredibly difficult to quantify, but there are heuristics.

Look at what your peers with a similar level of experience are doing.

Look at what you're committing to do during sprint planning or 1:1s with your manager. (Assuming you're in a reasonable organization with a healthy workload.)

Anything above that is deserving of a raise or promotion.

Hence the need for good managers to set expectations and manage timelines.

Sprint Goals.

Sprint goals are based on capacity, which is loosely defined by how much your team works. Defining how much you need to work by basing it on how much you should achieve, which is based on a number defined by how much you (and your team) work, is circular reasoning.